BioMetals

, Volume 24, Issue 6, pp 1079–1092

Physiological relevance and contribution to metal balance of specific and non-specific Metallothionein isoforms in the garden snail, Cantareus aspersus

  • Martina Höckner
  • Karin Stefanon
  • Annette de Vaufleury
  • Freddy Monteiro
  • Sílvia Pérez-Rafael
  • Òscar Palacios
  • Mercè Capdevila
  • Sílvia Atrian
  • Reinhard Dallinger
Article

DOI: 10.1007/s10534-011-9466-x

Cite this article as:
Höckner, M., Stefanon, K., de Vaufleury, A. et al. Biometals (2011) 24: 1079. doi:10.1007/s10534-011-9466-x

Abstract

Variable environmental availability of metal ions represents a constant challenge for most organisms, so that during evolution, they have optimised physiological and molecular mechanisms to cope with this particular requirement. Metallothioneins (MTs) are proteins that play a major role in metal homeostasis and as a reservoir. The MT gene/protein systems of terrestrial helicid snails are an invaluable model for the study of metal-binding features and MT isoform-specific functionality of these proteins. In the present study, we characterised three paralogous MT isogenes and their expressed products in the escargot (Cantareus aspersus). The metal-dependent transcriptional activation of the three isogenes was assessed using quantitative Real Time PCR. The metal-binding capacities of the three isoforms were studied by characterising the purified native complexes. All the data were analysed in relation to the trace element status of the animals after metal feeding. Two of the three C.aspersus MT (CaMT) isoforms appeared to be metal-specific, (CaCdMT and CaCuMT, for cadmium and copper respectively). A third isoform (CaCd/CuMT) was non-specific, since it was natively recovered as a mixed Cd/Cu complex. A specific role in Cd detoxification for CaCdMT was revealed, with a 80–90% contribution to the Cd balance in snails exposed to this metal. Conclusive data were also obtained for the CaCuMT isoform, which is involved in Cu homeostasis, sharing about 30–50% of the Cu balance of C. aspersus. No apparent metal-related physiological function was found for the third isoform (CaCd/CuMT), so its contribution to the metal balance of the escargot may be, if at all, of only marginal significance, but may enclose a major interest in evolutionary studies.

Keywords

CadmiumCopperZincMetallothioneinMolluscaPulmonata

Abbreviations

AAS

Atomic absorption spectrophotometry

CaMT

C. aspersus MT (global denomination)

CaCdMT

Cd-specific C. aspersus MT isoform

CaCuMT

Cu-specific C. aspersus MT isoform

CaCd/CuMT

Mixed metal C. aspersus MT isoform

ESI-MS

Electrospray ionization mass spectrometry

ESI-TOF MS

Time-of-flight electrospray ionization mass spectrometry

Copyright information

© Springer Science+Business Media, LLC. 2011

Authors and Affiliations

  • Martina Höckner
    • 1
  • Karin Stefanon
    • 1
  • Annette de Vaufleury
    • 2
  • Freddy Monteiro
    • 3
  • Sílvia Pérez-Rafael
    • 4
  • Òscar Palacios
    • 4
  • Mercè Capdevila
    • 4
  • Sílvia Atrian
    • 3
  • Reinhard Dallinger
    • 1
  1. 1.Institute of ZoologyUniversity of InnsbruckInnsbruckAustria
  2. 2.Department of Chrono-EnvironmentUniversity of Franche-ComtéBesançon CedexFrance
  3. 3.Departament de Genètica, Facultat de BiologiaUniversitat de BarcelonaBarcelonaSpain
  4. 4.Departament de Química, Facultat de CiènciesUniversitat Autònoma de BarcelonaBarcelonaSpain